https://github.com/jbossas/remoting-jmx/issues/41

You are also affected with:
https://developer.jboss.org/thread/279791
https://issues.jboss.org/browse/WFLY-11720?focusedCommentId=13697026&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel
jboss-marshalling should probably be updated.

I got the same error as on those cases when I upgraded to java 11.
java.lang.ExceptionInInitializerError
at org.jboss.marshalling.river.RiverMarshaller.<clinit>(RiverMarshaller.java:1335)
at org.jboss.marshalling.river.RiverMarshallerFactory.createMarshaller(RiverMarshallerFactory.java:54)
...
Caused by: java.lang.IllegalStateException: No standard field found for reverse order comparator!
at org.jboss.marshalling.river.Protocol.<clinit>(Protocol.java:287)
... 9 more

But because I got it a few months ago (I posted it to your github, but got no responce from there) I can't provide any details on how to reproduce it.
After a few days of debugging I tracked the cause down to the pre-JDK11 jboss-marshalling version you are depending on.